[Bug c++/105297] [12 Regression] new modules 'xtreme' test cases FAILs

["guojiufu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105297

--- Comment #15 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
(In reply to Patrick Palka from comment #13)
> (In reply to Jiu Fu Guo from comment #11)
> > (In reply to Patrick Palka from comment #10)
> > > 
> > > Interestingly that doesn't seem to make a difference.  What seems to matter
> > > is whether the constexpr function modifies the CONSTRUCTOR that it returns:
> > > 
> > > constexpr auto foo() {
> > >   struct S { int d; } t = {};
> > >   t.d = 0; // doesn't ICE if this line is commented out
> > >   return t;
> > > }
> > > 
> > > template<int>
> > > int bar() {
> > >   constexpr auto t = foo();
> > >   return 0;
> > > }
> > 
> > Right, it is weird. Some PRs on Xtreme-* failure (including ICE) were also
> > reported before. e.g. PR100052, PR101853, PR99910.  As commented in those
> > PRs, these may be random failures, and changes in headers that could expose
> > the ICE.
> > I'm also wondering if this may be an issue hidden inside somewhere (GC?).
> 
> In this case I suspect it's just a bug in the modules code, I opened
> PR105322 to track it.

Oh, thanks!  This failure seems only about the module code on 'struct member
cross functions'.